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//---------------------------------------------------------------------------//
// $Id: x04.cc,v 1.6 2004/03/03 17:41:16 andrewross Exp $
//---------------------------------------------------------------------------//
//
//---------------------------------------------------------------------------//
// Copyright (C) 2004 Andrew Ross <andrewr@coriolis.greenend.org.uk>
// Copyright (C) 2004 Alan W. Irwin
//
// This file is part of PLplot.
//
// PLplot is free software; you can redistribute it and/or modify
// it under the terms of the GNU Library General Public License as published by
// the Free Software Foundation; version 2 of the License.
//
// PLplot is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Library General Public License for more details.
//
// You should have received a copy of the GNU Library General Public License
// along with PLplot; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//---------------------------------------------------------------------------//
//
//---------------------------------------------------------------------------//
// Implementation of PLplot example 4 in C++.
//---------------------------------------------------------------------------//
#include "plstream.h"
#include <iostream>
#include <cmath>
#ifdef USE_NAMESPACE
using namespace std;
#endif
class x04 {
public:
x04(int, char **);
void plot1(int);
private:
// Class data
plstream *pls;
};
x04::x04( int argc, char ** argv ) {
// plplot initialization
pls = new plstream();
// Parse and process command line arguments.
pls->ParseOpts( &argc, argv, PL_PARSE_FULL );
// Initialize PLplot.
pls->init();
pls->font(2);
// Make log plots using two different styles.
plot1(0);
plot1(1);
// pls->end();
delete pls;
}
// Log-linear plot.
void x04::plot1( int type ) {
int i;
PLFLT *freql = new PLFLT[101];
PLFLT *ampl = new PLFLT[101];
PLFLT *phase = new PLFLT[101];
PLFLT f0, freq;
pls->adv(0);
// Set up data for log plot.
f0 = 1.0;
for (i = 0; i <= 100; i++) {
freql[i] = -2.0 + i / 20.0;
freq = pow(10.0, freql[i]);
ampl[i] = 20.0 * log10(1.0 / sqrt(1.0 + pow((freq / f0), 2.)));
phase[i] = -(180.0 / M_PI) * atan(freq / f0);
}
pls->vpor(0.15, 0.85, 0.1, 0.9);
pls->wind(-2.0, 3.0, -80.0, 0.0);
// Try different axis and labelling styles.
pls->col0(1);
switch (type) {
case 0:
pls->box("bclnst", 0.0, 0, "bnstv", 0.0, 0);
break;
case 1:
pls->box("bcfghlnst", 0.0, 0, "bcghnstv", 0.0, 0);
break;
}
// Plot ampl vs freq.
pls->col0(2);
pls->line(101,freql, ampl);
pls->col0(1);
pls->ptex(1.6, -30.0, 1.0, -20.0, 0.5, "-20 dB/decade");
// Put labels on.
pls->col0(1);
pls->mtex("b", 3.2, 0.5, 0.5, "Frequency");
pls->mtex("t", 2.0, 0.5, 0.5, "Single Pole Low-Pass Filter");
pls->col0(2);
pls->mtex("l", 5.0, 0.5, 0.5, "Amplitude (dB)");
// For the gridless case, put phase vs freq on same plot.
if (type == 0) {
pls->col0(1);
pls->wind(-2.0, 3.0, -100.0, 0.0);
pls->box("", 0.0, 0, "cmstv", 30.0, 3);
pls->col0(3);
pls->line(101,freql, phase);
pls->col0(3);
pls->mtex("r", 5.0, 0.5, 0.5, "Phase shift (degrees)");
}
delete[] freql;
delete[] ampl;
delete[] phase;
}
int main( int argc, char ** argv ) {
x04 *x = new x04( argc, argv );
delete x;
}
//---------------------------------------------------------------------------//
// End of x04.cc
//---------------------------------------------------------------------------//
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